199680809 has 2 divisors, whose sum is σ = 199680810. Its totient is φ = 199680808.

The previous prime is 199680797. The next prime is 199680851. The reversal of 199680809 is 908086991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 154455184 + 45225625 = 12428^2 + 6725^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-199680809 is a prime.

It is not a weakly prime, because it can be changed into another prime (199680409) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99840404 + 99840405.

It is an arithmetic number, because the mean of its divisors is an integer number (99840405).

Almost surely, 2^199680809 is an apocalyptic number.

It is an amenable number.

199680809 is a deficient number, since it is larger than the sum of its proper divisors (1).

199680809 is an equidigital number, since it uses as much as digits as its factorization.

199680809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 279936, while the sum is 50.

The square root of 199680809 is about 14130.8460114743. The cubic root of 199680809 is about 584.4922752763.

The spelling of 199680809 in words is "one hundred ninety-nine million, six hundred eighty thousand, eight hundred nine".